4D Zonal Classification of Time-Periodic Flows: Formulation and Computational Methods

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K13779
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Foundations of mathematics/Applied mathematics
• Research Institution: Waseda University
• Principal Investigator: Kenji Takizawa 早稲田大学, 理工学術院, 准教授 (60415809)
• Co-Investigator(Kenkyū-buntansha): 野津 裕史 金沢大学, 数物科学系, 准教授 (00588783)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 流体 / 滞留時間 / 離散化 / space-time法 / 特性線法

Outline of Final Research Achievements

To understand time-periodic flow behavior, we focus on particle residence time. Residence time can be computed with the Eulerian form of the equations, and thus can be defined over the entire domain as a time-dependent variable.
We use aorta flow as example of pulsating inflow, and turbomachinery as a moving-boundary problem. To obtain periodic behavior of the residence time, we keep computing the time-periodic flow. The residence time at the outlet can be estimated with a simple theory and we compare that to the computed value. Residence time lower than the theoretical value implies presence of regions where the flow is not connected to the rest of the domain. Such regions can be detected with the residence time by comparing it to the computation duration. To increase the calculation accuracy, we introduced a characteristic-based method, refinement techniques, and new ways of calculating the stabilization parameters.

Free Research Field

数値解析